9
votes
Two antennas on different sides of a building
As one solution, you can combine the antennas with a power divider. See How to combine two 50 Ω antennas such that they appear as one 50 Ω load?
This makes your pair of antennas into a phased array. ...
- 50.8k
8
votes
If i connect two antennas to one radio using a t connector will it work?
Assuming that both antennas are 50 Ω resistive, they will combine in parallel for a 25 Ω load impedance when transmitting. This will cause the transmitter to see a 2:1 SWR. This is a 0.333 voltage ...
- 18.3k
8
votes
If i connect two antennas to one radio using a t connector will it work?
If I connect two antennas to one radio using a t connector will it work?
That depends on your t-connector.
If your tee really is just a branch in the inner conductor and connected outer conducters, ...
- 14.7k
7
votes
Accepted
Can these in-band spurs from rpitx be eliminated somehow?
I can't dig up my source for this, but I'm pretty sure these spurs are just the result of rpitx using a fractional-N PLL (that isn't in any way optimized for phase noise) to generate a square wave. ...
- 10.7k
6
votes
Accepted
Ideal antenna type for FM 2 meters?
Fundamental questions in a choice of antenna design are:
Does it have the proper polarization (vertical, horizontal, or circular)?
Does it have the proper radiation pattern?
Some secondary issues ...
- 23.7k
6
votes
Is the National Calling Frequency actually used?
146.520 MHz is the national calling frequency for FM voice. It's a "simplex" frequency, meaning that you call on this frequency and then listen for a reply on the same frequency. (It is "national" ...
6
votes
If i connect two antennas to one radio using a t connector will it work?
For receiving it should work up to a certain level.
However, the impedance will be completely different from that of a single antenna. So the SWR will be too high for transmitting and reception will ...
- 783
6
votes
What frequencies in 118–173 MHz can I transmit on without a license in Canada?
None. Basically, aside from a few ISM bands, none of which are covered by your radio, you can transmit nowhere without a license, unless you're using hardware that restricts you to legal usage (e.g. ...
- 14.7k
6
votes
Accepted
Recomended coax for 100ft (2m/70cm)
According to this online coax loss calculator, the loss of 50 feet of new Belden 9258 RG-8X with an antenna with an SWR of 1.5 is 4.29 dB at 450 MHz (UHF), so the loss for 100 feet of the same coax ...
- 8,982
6
votes
Swapping crystal from HF to VHF in a QRP tranceiver
Too Long; Didn't Read (tl;dr)
That circuit was designed for 40 m. You can't modify it just by replacing the quartz crystal to work on 2 m.
What Would Need to Change?
So what you've found is a circuit ...
- 14.7k
5
votes
What is the minimum signal strength I need to receive?
At 8W, the power from the radio is 9.03dB.
With the cable losses of the receiving station being 1.5dB (1.41W), and the antenna receiving 1.733e-8W, it appears the received signal will never make ...
- 50.8k
5
votes
Website for satellite down/uplink frequencies and live footprint?
n2yo.com is a wonderful resource for keeping track of all of the orbiting satellites. It has many resources for tracking info to enter into tracking software and other places. It also shows a live ...
- 1,276
4
votes
While backpacking, is it worth mounting the antenna to the backpack frame (above my head)?
If you are worried about range the best thing you can do is get a full sized antenna that you can remotely mount, either on your backpack or elsewhere, and feed it with a short feed line (pigtail). ...
- 191
4
votes
Accepted
2 Meter horizontal or vertical dipole polarization?
For VHF, choice of polarization is not up to your desired radiation pattern, but who you want to be able to communicate with. In HF, the ionosphere causes random rotation of your signal's polarization,...
- 23.7k
4
votes
Accepted
HF/VHF antenna for high altitude balloon
It is equally important to consider the pattern of the antenna. If you hang a 1/2 wave antenna vertically, there will be minimal radiation in the earth facing direction. This will be most problematic ...
- 18.3k
4
votes
Why are 2m and 70cm the common frequencies on HTs?
History and tradition are good choices of words, yes. Historically, they have been the most popular bands for mobile work; the antennas are small enough for a vehicle and many repeaters have been ...
- 7,604
4
votes
Accepted
Why are 2m and 70cm the common frequencies on HTs?
Worthy of mention is that 432MHz is a harmonic of 144MHz, meaning that the antenna can be much simpler; if it's (electrically) an odd number of half-waves on 2m, it's also an odd number of half-waves ...
- 4,429
4
votes
Accepted
Using a Baofeng UV-5R V2+ as a Portable Packet Radio
As far as I know, none of that series "speaks" APRS by itself, so you'd need your external controller to generated the AFSK tones.
Whilst it's possible to generate AFSK at such low rates with an ...
- 14.7k
4
votes
Accepted
What gain and power are required for successful DX contacts on 2m/70cm bands in CW?
I will talk about my experiences with 2m here - 70cm is similar, except (and anybody who knows better than me please correct me) there is no sporadic-E at all ever on 70cm.
It all depends on ...
- 4,429
4
votes
1/8 wave 3-element 2m beam antenna
Yagi antennas require an exact set of lengths and spacings to work properly.
The lengths are all near a half wave but there is some subtle tuning to get the currents to the appropriate phase.
Spacing ...
- 9,609
4
votes
Accepted
A new ham should start with Digital or Analog Portable Radio?
I would suggest Analog FM only, to start with.
Most repeaters are still FM, you won't be missing out on any coverage if you don't have digital.
The digital landscape is still a bit fragmented, with ...
- 9,609
3
votes
What is the minimum signal strength I need to receive?
From the symptoms you state of not being able to hear transmissions from identical setups only 4 miles from each other, and then being able to have one person receive with the rubber duck antenna, it ...
- 357
3
votes
Is the National Calling Frequency actually used?
I have my VHF rig in my pickup truck set to 146.52 MHz all of the time when I am driving. In an hour's time I would guess I hear maybe 3 or 4 copyable signals. My main use is to help someone out by ...
- 2,898
3
votes
2 antennas and 2 amplifiers connected to same exciter radio
Combining multiple power amplifiers is a standard technique for generating high power from a number of lower-power components. You feed all amplifiers with the same input (split the input with ...
3
votes
Accepted
Are any handsets compliant with Canadian regs usable on both 2M amateur and 2M commercial bands? Is this even possible?
According to Alan McLean of Industry Canada if a radio approved for use in LMR service in Canada, for example, can be software reprogrammed (without hardware modifications) to be used on the amateur ...
- 18.3k
3
votes
Accepted
Proper magnetic mount placement on roof
When dealing with UHF and VHF communications, height is often the determining factor of range for line of sight conditions. If there are obstructions that height cannot overcome, then more effective ...
- 18.3k
3
votes
Is there a trick for reaching a repeater "through" terrain?
Reaching a repeater 30 miles (48 km) away with a mountain in between, with a handheld, sounds nearly impossible. Reaching a repeater 15 miles away with a ridge in the way with a handheld sounds very ...
- 8,982
3
votes
What gain and power are required for successful DX contacts on 2m/70cm bands in CW?
My experienses on 2 meters when I was living in southern Finland (near Helsinki). My Finnisf call sign was (and still is) OH2AXE. I did not have 70 cm equipment.
Antenna: 2 x 2 stack of double hybrid ...
3
votes
Squelch won't stay open on FM 2 meter band
I can think of two possible issues, but both of them are "something to do with the radio".
The first is that something in the signal you're listening to is tweaking the Baofeng squelch tail ...
- 10.7k
3
votes
Squelch won't stay open on FM 2 meter band
My personal experience: Baofeng UV-5R, works fine with stock rubber ducky antenna. Made a simple quarter-wave dipole antenna, connected to my radio with about 10 feet of cable. It transmitted much ...
- 33
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